JavaScript is disabled for your browser. Some features of this site may not work without it.

Data from: No assortative mating based on size in black guillemots breeding in the Canadian Arctic

Berzins LL, Gilchrist HG, Burness G

Date Published: May 27, 2015

DOI: http://dx.doi.org/10.5061/dryad.1bm5t

Files in this package

Content in the Dryad
Digital Repository is offered "as is." By downloading files, you agree
to the Dryad Terms of Service.
To the extent possible under law, the authors have waived all copyright
and related or neighboring rights to this data.

AbstractThe Black Guillemot (Cepphus grylle) is a monomorphic, socially monogamous member of the Alcidae. Although aspects of their breeding and foraging ecology have been extensively studied, less is known about possible sex-based differences in morphology, nor whether Black Guillemots mate assortatively based on body size. Using molecular techniques, we identified the sex of 26 male and 21 female Black Guillemots captured in the Canadian Arctic, and measured six external body measurements: outer tarsus length, wing length, culmen length, bill depth, head plus bill length and body mass to test for sexual size dimorphism (SSD) and assortative mating. Overall, males were 1.7% and 8% larger than females in outer tarsus length and bill depth, respectively. Within breeding pairs, bill depth was the most dimorphic trait. Despite these morphological differences no evidence of assortative mating based upon body size was found. Thus, mate choice for body size does not appear to be an underlying mechanism of SSD in bill depth in Black Guillemots.